package org.xg.study.pd;

import java.util.concurrent.atomic.AtomicReference;

/**
 * @author CMG
 * @version 1.0
 * @cLassName Singleton_06
 * @description CAS 【AtomicReference】(线程安全)
 * @date 2021/9/14 9:47
 **/
public class Singleton_06 {
    private static final AtomicReference<Singleton_06> INSTANCE = new AtomicReference<>();

    private static Singleton_06 instance;

    private Singleton_06(){

    }

    public static final Singleton_06 getInstance(){
        for(;;){
            Singleton_06 instance = INSTANCE.get();
            if(null != instance){
                return instance;
            }
            INSTANCE.compareAndSet(null,new Singleton_06());
            return INSTANCE.get();
        }
    }

    public static void main(String[] args) {
        System.out.println(Singleton_06.getInstance());
        System.out.println(Singleton_06.getInstance());
        System.out.println(Singleton_06.getInstance());
    }
}
